[NSRCA-discussion] db Rules

[Bob Kane]

Do they have a distance parameter defined?  The dB number by itself is meaningless. 

 Bob Kane
getterflash at yahoo.com




________________________________
From: Scott Pavlock <f3aflyer7 at gmail.com>
To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, May 20, 2009 8:19:03 AM
Subject: Re: [NSRCA-discussion] db Rules

Bob 

The club has set 78db as the standard for quiet flyers. Thanks for the info.

Mike


On Wed, May 20, 2009 at 7:09 AM, Bob Kane <getterflash at yahoo.com> wrote:

>From the AMA Competition Regulations for RC Aerobatics (I removed the text on motor type and scoring penalties)

4.2: Noise Limit. <snip> The maximum noise level for all classes shall be 96 decibels measured at three (3) meters from the center line of the model with the model standing on concrete or macadam, and 94 dB if an earth or short grass surface must be used All measurements will be taken perpendicular to the fuselage centerline on the right hand side of the model, with the nose of the model aircraft pointed into the wind, with motor running at full power; the microphone to be placed on a stand 30 centimeters above the ground and in line with the motor. No noise reflecting objects shall be nearer than three (3) meters to model or microphone. <snip>

What actual dB number you use is up to the club. 94 dB would be too loud for a park flyer. You might want to measure an acceptable plane to see what the number is and use that as the standard. You could also measure a plane considered too loud and see what it measures. The tough thing is "loud" and "unpleasant" are not easily related.

 Bob Kane
getterflash at yahoo.com




________________________________
From: Scott Pavlock <f3aflyer7 at gmail.com>
To: NSRCA Discussion List <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, May 20, 2009 7:28:05 AM

Subject: [NSRCA-discussion] db Rules


Our club has recently added more flying times for quiet flyers. But we need to have our planes db'ed before we can fly in these new very early hours.  Where can I find a set of guidelines on how a plane should be properly db'ed ?

Regards 
Mike


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